1. Field of the Invention
This invention relates in general to tamper-proof plastic closures for containers having a screw-threaded neck, and has specific reference to closures of this type comprising in addition a safety means intended more particularly for containers such as bottles or the like which should not be opened by children, for instance bottles containing drugs or other dangerous products.
2. Description of the Prior Art
In the U.S. Pat. No. 3,863,796 to Roy there is disclosed a safety closure device comprising an internal plug screwed to the neck of the container and housed in a covering cap formed on the inner peripheral surface of its upper wall with a series of teeth adapted to engage corresponding teeth formed on the outer peripheral surface of the upper wall of said plug when a pressure is exerted in the axial direction throughout the cap surface against the force of a central spring. However, this device is not tamperproof, since even a child can produce this meshing engagement by merely depressing the cap as a whole.